X-ray for natural and cultural heritage objects: A matter of size and contrast

abstract

English

Computed tomography (CT) for Natural and Cultural Heritage is becoming more and more used for whole objects, showing incredible images of the surface and the internal morphology of artefacts. CT systems use the density of the materials to create 2D images made of grey values. These images are reconstructed together to create a 3D volume of the object scanned. Though, CT has a richer variety of results than pure images. Indeed, X-ray computed tomography can be used for measurements (2D, 3D), features morphology, topology of (sub)surfaces, layer correlation, particles shape and distribution, component determination, porosity, cracks detection, past restoration, and the list is continuously improving and increasing. Correlation with acknowledged methods, such as optical and scanning electron microscope, is also strongly developing to verify some information, or enhance the interpretation. CT results observation and quantification are bound to the resolution and contrast of the data. These are related to the sample to be scanned (size, components), to the parameters of the device (detector-sample-X-ray distance), and finally to the volume reconstruction and filtering options (blur, alignment). Phase-contrast retrieval is one CT technique that enhances the contrast between the materials. It can be crucial for the visualisation of a painting canvas (organic fibres) and the painted layers (principally inorganic particles), for example. Generally, the larger the sample, the lower the resolution. Which is why the analysis of micro-samples can give other information than a whole object. The easier access to laboratory CT with resolution comparable to second generation synchrotron makes them also appealing. We would like to present studies of original paintings, archaeological ceramic and microfossils, showing the CT achievable results according to the type of sample correlated to the question related to each object. Paintings are mostly about layering, particles distribution and canvas, while archaeological ceramics temper and shaping methods. Finally, microfossils are about morphology, shape, bioerosion and comparison between specimens.

Computed tomography; Non-destructive; Submicron; 3D; Cultural Heritage; Natural Heritage; Painting; Archaeological Ceramic; Microfossils

JAQUES, V.; PETŘÍK, J.; SLAVIČEK, K.; HOLCOVÁ, K.; VAŇATKOVÁ, K.; PARKKONEN, J.; KERKHOFF, M.; ZIKMUND, T.; KAISER, J.

8. 5. 2023

Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa

Lisbon

978-989-9164-08-6

TECHNART2023 - Non-destructive and Microanalytical Techniques in Art and Cultural Heritage: Book of Abstracts

449

https://novaresearch.unl.pt/en/publications/technart2023-non-destructive-and-microanalytical-techniques-in-ar